In recent years, there has been increasing research effort to develop metal structures in the nanoscale range (that is, in the 0.1 to 100 nm range) for a variety of technological applications such as, for example, electronic and optical devices, labeling of biological material, magnetic recording media, and quantum computing.
Numerous approaches have been developed for synthesizing/fabricating metal nanostructures such as, for example, metal nanowires, nanorods, nanotubes, and nanoribbons. Current approaches include, for example, fabricating metal nanowires by the electroless deposition of metal into the pores of nanoporous membranes by a metal amplification process (see, for example, Barbic et al., J. Appl. Phys., 91, 9341 (2002)) and fabricating metal nanowires/nanotubes by a vapor-liquid-solid (VLS) process in which involves the dissolution of gaseous reactants in nanosized liquid droplets of the metal solvent, followed by nucleation and growth of single crystalline wires (see, for example, Ding et al., J. Phys. Chem. B 108, 12280 (2004)). A challenge that remains, however, is controlling the size and shape of metallic nanostructures, as well as their orientation and distribution, particularly on a large scale.